The effects of microgeometries in carbide twist drill on dry drilling of cast iron

Abstract

The drilling process is one of the most used methods in producing holes worldwide. An important requirement in the drilling process is the need to generate a hole that satisfies the dimensional and geometrical requirements in just one operation. That leads practitioners to an inner awareness about the geometry of the tool, as well as the strict monitoring of the wear of its cutting edges. However, another relevant factor is the need to reduce process waste. In the case of machining processes, discarding cutting fluids that have arrived at the end of their usefulness presents a relevant management problem. There have been, therefore, increasing efforts towards the possibility of working with minimum amounts of fluid, or even simply the complete elimination of its use. This need to reduce fluid waste can have an adverse effect, however, on both tool life and operations’ performances. In cases of drilling, ductile iron-efficient monitoring of wearing patterns can reduce premature tool breakages. This study evaluates effects on tool life and wearing with hard metal twist drill bits used in drilling ductile iron in the absence of refrigerant. This study includes microgeometry and the type of coating used on the tools. Wearing and tool life behaviors are also studied.